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112 lines
2.5 KiB
C++
112 lines
2.5 KiB
C++
// Copyright 2009-2021 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include "intrinsics.h"
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#include "sysinfo.h"
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#include "atomic.h"
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namespace embree
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{
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/*! system barrier using operating system */
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class BarrierSys
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{
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public:
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/*! construction / destruction */
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BarrierSys (size_t N = 0);
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~BarrierSys ();
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private:
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/*! class in non-copyable */
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BarrierSys (const BarrierSys& other) DELETED; // do not implement
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BarrierSys& operator= (const BarrierSys& other) DELETED; // do not implement
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public:
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/*! initializes the barrier with some number of threads */
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void init(size_t count);
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/*! lets calling thread wait in barrier */
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void wait();
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private:
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void* opaque;
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};
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/*! fast active barrier using atomic counter */
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struct BarrierActive
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{
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public:
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BarrierActive ()
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: cntr(0) {}
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void reset() {
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cntr.store(0);
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}
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void wait (size_t numThreads)
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{
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cntr++;
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while (cntr.load() != numThreads)
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pause_cpu();
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}
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private:
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std::atomic<size_t> cntr;
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};
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/*! fast active barrier that does not require initialization to some number of threads */
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struct BarrierActiveAutoReset
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{
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public:
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BarrierActiveAutoReset ()
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: cntr0(0), cntr1(0) {}
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void wait (size_t threadCount)
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{
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cntr0.fetch_add(1);
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while (cntr0 != threadCount) pause_cpu();
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cntr1.fetch_add(1);
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while (cntr1 != threadCount) pause_cpu();
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cntr0.fetch_add(-1);
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while (cntr0 != 0) pause_cpu();
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cntr1.fetch_add(-1);
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while (cntr1 != 0) pause_cpu();
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}
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private:
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std::atomic<size_t> cntr0;
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std::atomic<size_t> cntr1;
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};
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class LinearBarrierActive
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{
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public:
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/*! construction and destruction */
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LinearBarrierActive (size_t threadCount = 0);
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~LinearBarrierActive();
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private:
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/*! class in non-copyable */
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LinearBarrierActive (const LinearBarrierActive& other) DELETED; // do not implement
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LinearBarrierActive& operator= (const LinearBarrierActive& other) DELETED; // do not implement
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public:
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/*! initializes the barrier with some number of threads */
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void init(size_t threadCount);
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/*! thread with threadIndex waits in the barrier */
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void wait (const size_t threadIndex);
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private:
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volatile unsigned char* count0;
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volatile unsigned char* count1;
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volatile unsigned int mode;
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volatile unsigned int flag0;
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volatile unsigned int flag1;
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volatile size_t threadCount;
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};
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}
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